spring cloud 网卡选择

Myth丶恋晨 2022-01-12 07:07 229阅读 0赞

spring-cloud-commons项目为Spring Cloud生态提供了顶层的抽象和基础设施的实现。  
网络这个最基本的基础设施也是在这里有对应的实现：InetUtils、InetUtilsProperties和UtilAutoConfiguration提供了网络配置相关的功能。  
[相关配置的spring cloud官方文档][spring cloud]

springcloud 中选择网卡的源码（可以从 HostInfoEnvironmentPostProcessor 切入）：

public InetAddress findFirstNonLoopbackAddress() {
        InetAddress result = null;
        try {
            int lowest = Integer.MAX_VALUE;
            for (Enumeration < NetworkInterface > nics = NetworkInterface
                .getNetworkInterfaces(); nics.hasMoreElements();) {
                NetworkInterface ifc = nics.nextElement();
                if (ifc.isUp()) {
                    log.trace("Testing interface: " + ifc.getDisplayName());
                    if (ifc.getIndex() < lowest || result == null) {
                        lowest = ifc.getIndex();
                    } else if (result != null) {
                        continue;
                    }
    
                    // @formatter:off
                    if (!ignoreInterface(ifc.getDisplayName())) {
                        for (Enumeration < InetAddress > addrs = ifc
                            .getInetAddresses(); addrs.hasMoreElements();) {
                            InetAddress address = addrs.nextElement();
                            if (address instanceof Inet4Address &&
                                !address.isLoopbackAddress() &&
                                !ignoreAddress(address)) {
                                log.trace("Found non-loopback interface: " +
                                    ifc.getDisplayName());
                                result = address;
                            }
                        }
                    }
                    // @formatter:on
                }
            }
        } catch (IOException ex) {
            log.error("Cannot get first non-loopback address", ex);
        }
    
        if (result != null) {
            return result;
        }
    
        try {
            return InetAddress.getLocalHost();
        } catch (UnknownHostException e) {
            log.warn("Unable to retrieve localhost");
        }
    
        return null;
    }

所以spring cloud默认是会采用绑定了ip的最后一块网卡，如果与实际需求不对等的话，则需要通过配置进行手动选择，无论是手动忽略某个网卡还是手动指定ip。

配置可以覆盖自动选择的源码：

public class HostInfoEnvironmentPostProcessor
    		implements EnvironmentPostProcessor, Ordered {
    
    	// Before ConfigFileApplicationListener
    	private int order = ConfigFileApplicationListener.DEFAULT_ORDER - 1;
    
    	@Override
    	public int getOrder() {
    		return this.order;
    	}
    
    	@Override
    	public void postProcessEnvironment(ConfigurableEnvironment environment,
    			SpringApplication application) {
    		InetUtils.HostInfo hostInfo = getFirstNonLoopbackHostInfo(environment);
    		LinkedHashMap<String, Object> map = new LinkedHashMap<>();
    		map.put("spring.cloud.client.hostname", hostInfo.getHostname());
    		map.put("spring.cloud.client.ip-address", hostInfo.getIpAddress());
    		MapPropertySource propertySource = new MapPropertySource(
    				"springCloudClientHostInfo", map);
    		environment.getPropertySources().addLast(propertySource);
    	}
    
    	private HostInfo getFirstNonLoopbackHostInfo(ConfigurableEnvironment environment) {
    		InetUtilsProperties target = new InetUtilsProperties();
    		ConfigurationPropertySources.attach(environment);
    		Binder.get(environment).bind(InetUtilsProperties.PREFIX,
    				Bindable.ofInstance(target));
    		try (InetUtils utils = new InetUtils(target)) {
    			return utils.findFirstNonLoopbackHostInfo();
    		}
    	}
    
    }

[spring cloud]: https://cloud.spring.io/spring-cloud-static/spring-cloud.html#ignore-network-interfaces